Shanghai has been experiencing the Omicron wave since March 2022. Though several
studies have evaluated the risk factors of severe infections, the analyses of BA. 2 infection …

Background The elderly are highly vulnerable to severe COVID-19. Waning immunity and
emergence of Omicron have caused concerns about reduced effectiveness of COVID-19 …

We conducted a matched retrospective cohort study of two cohorts to estimate inactivated
vaccine effectiveness (VE) and its comparative effectiveness of booster dose among older …

An outbreak of COVID-19 caused by the SARS-CoV-2 Omicron BA. 2 sublineage occurred
in Shanghai, China from February 26 to June 30, 2022. We use official reported data …

Background Vaccination reduces COVID-19-related hospitalization among older adults.
However, how SARS-CoV-2 infection and vaccine regimens affect vaccine-elicited immunity …

The COVID-19 outbreak highlights the vulnerability to novel infections, and vaccination
remains a foreseeable method to return to normal life. However, infrastructure is inadequate …

Introduction Understanding the changing epidemiology of adults hospitalized with
coronavirus disease 2019 (COVID-19) informs research priorities and public health policies …

Vaccination is the primary defense against severe acute respiratory syndrome coronavirus
2, especially among older adults and those with chronic conditions. Using a nationally …

Background: The emergency use authorization for coronavirus disease 2019 (COVID-19)
vaccines brought both hopes and concerns to the Americans and others. We aimed to …

Background Older adults are at increased risk of SARS-CoV-2 Omicron infection and severe
disease, especially those in congregate living settings, despite high SARS-CoV-2 vaccine …